Funny, I've been looking for alternatives to a Romin Evo for a bit now. I just don't want any Specialized on my bike and the titanium railed non-uber padded Romin Evo has red on it, too. Anyways, the Romin Evo looks like its better for getting an aero position, which is how they advertise it. I'm surprised to hear you noticed no difference between the Romin and the Romin Evo in that regard.
Yeah, the Romin's never give me trouble with aero. A lot of people don't seem to care for the nose, but I tend to ride pretty nose-down on my Romin--I don't try to level it out nose to tail like most saddles, but have the center section tilted one or two degrees down. That keep the nose low for aero and the rear flare in place to push back against.
The Evo has a less pronounced nose, but aside form that and padding they ought to be basically identical.
And the more I think about it, the Toupe is far more like the Antares than the Romin is. The Antares is super flat, and the Toupe is just the same. My Selle Italia SLR Superflow is also pretty flat like the Antares with just a little rounding at the wings, but much less than on the Arione. It also has a nutso huge cutout, which is fantastic.